Introduce cleanup functions for cap_free

Unfortunately a different cleanup function is necessary per type,
because cap_t** and char** are incompatible with void**.

5 files changed, 55 insertions, 68 deletions

diff --git a/src/core/dbus-execute.c b/src/core/dbus-execute.c
index b79a456455..4e9529708d 100644
--- a/src/core/dbus-execute.c
+++ b/src/core/dbus-execute.c
@@ -29,6 +29,7 @@
 #include "fileio.h"
 #include "execute.h"
 #include "dbus-execute.h"
+#include "capability.h"
 
 BUS_DEFINE_PROPERTY_GET_ENUM(bus_property_get_exec_output, exec_output, ExecOutput);
 
@@ -319,9 +320,8 @@ static int property_get_capabilities(
                 sd_bus_error *error) {
 
         ExecContext *c = userdata;
-        char *t = NULL;
+        _cleanup_cap_free_charp_ char *t = NULL;
         const char *s;
-        int r;
 
         assert(bus);
         assert(reply);
@@ -335,12 +335,7 @@ static int property_get_capabilities(
         if (!s)
                 return -ENOMEM;
 
-        r = sd_bus_message_append(reply, "s", s);
-
-        if (t)
-                cap_free(t);
-
-        return r;
+        return sd_bus_message_append(reply, "s", s);
 }
 
 static int property_get_syscall_filter(
diff --git a/src/core/execute.c b/src/core/execute.c
index 39c0fed7ac..4317afad8a 100644
--- a/src/core/execute.c
+++ b/src/core/execute.c
@@ -650,14 +650,13 @@ static int enforce_groups(const ExecContext *context, const char *username, gid_
 }
 
 static int enforce_user(const ExecContext *context, uid_t uid) {
-        int r;
         assert(context);
 
         /* Sets (but doesn't lookup) the uid and make sure we keep the
          * capabilities while doing so. */
 
         if (context->capabilities) {
-                cap_t d;
+                _cleanup_cap_free_ cap_t d = NULL;
                 static const cap_value_t bits[] = {
                         CAP_SETUID,   /* Necessary so that we can run setresuid() below */
                         CAP_SETPCAP   /* Necessary so that we can set PR_SET_SECUREBITS later on */
@@ -677,23 +676,16 @@ static int enforce_user(const ExecContext *context, uid_t uid) {
                 /* Second step: set the capabilities. This will reduce
                  * the capabilities to the minimum we need. */
 
-                if (!(d = cap_dup(context->capabilities)))
+                d = cap_dup(context->capabilities);
+                if (!d)
                         return -errno;
 
                 if (cap_set_flag(d, CAP_EFFECTIVE, ELEMENTSOF(bits), bits, CAP_SET) < 0 ||
-                    cap_set_flag(d, CAP_PERMITTED, ELEMENTSOF(bits), bits, CAP_SET) < 0) {
-                        r = -errno;
-                        cap_free(d);
-                        return r;
-                }
-
-                if (cap_set_proc(d) < 0) {
-                        r = -errno;
-                        cap_free(d);
-                        return r;
-                }
+                    cap_set_flag(d, CAP_PERMITTED, ELEMENTSOF(bits), bits, CAP_SET) < 0)
+                        return -errno;
 
-                cap_free(d);
+                if (cap_set_proc(d) < 0)
+                        return -errno;
         }
 
         /* Third step: actually set the uids */
@@ -2000,37 +1992,37 @@ void exec_context_dump(ExecContext *c, FILE* f, const char *prefix) {
                         prefix, yes_no(c->tty_vhangup),
                         prefix, yes_no(c->tty_vt_disallocate));
 
-        if (c->std_output == EXEC_OUTPUT_SYSLOG || c->std_output == EXEC_OUTPUT_KMSG || c->std_output == EXEC_OUTPUT_JOURNAL ||
-            c->std_output == EXEC_OUTPUT_SYSLOG_AND_CONSOLE || c->std_output == EXEC_OUTPUT_KMSG_AND_CONSOLE || c->std_output == EXEC_OUTPUT_JOURNAL_AND_CONSOLE ||
-            c->std_error == EXEC_OUTPUT_SYSLOG || c->std_error == EXEC_OUTPUT_KMSG || c->std_error == EXEC_OUTPUT_JOURNAL ||
-            c->std_error == EXEC_OUTPUT_SYSLOG_AND_CONSOLE || c->std_error == EXEC_OUTPUT_KMSG_AND_CONSOLE || c->std_error == EXEC_OUTPUT_JOURNAL_AND_CONSOLE) {
-                char *fac_str, *lvl_str;
-                int r;
+        if (c->std_output == EXEC_OUTPUT_SYSLOG ||
+            c->std_output == EXEC_OUTPUT_KMSG ||
+            c->std_output == EXEC_OUTPUT_JOURNAL ||
+            c->std_output == EXEC_OUTPUT_SYSLOG_AND_CONSOLE ||
+            c->std_output == EXEC_OUTPUT_KMSG_AND_CONSOLE ||
+            c->std_output == EXEC_OUTPUT_JOURNAL_AND_CONSOLE ||
+            c->std_error == EXEC_OUTPUT_SYSLOG ||
+            c->std_error == EXEC_OUTPUT_KMSG ||
+            c->std_error == EXEC_OUTPUT_JOURNAL ||
+            c->std_error == EXEC_OUTPUT_SYSLOG_AND_CONSOLE ||
+            c->std_error == EXEC_OUTPUT_KMSG_AND_CONSOLE ||
+            c->std_error == EXEC_OUTPUT_JOURNAL_AND_CONSOLE) {
 
-                r = log_facility_unshifted_to_string_alloc(c->syslog_priority >> 3, &fac_str);
-                if (r < 0)
-                        fac_str = NULL;
+                _cleanup_free_ char *fac_str = NULL, *lvl_str = NULL;
 
-                r = log_level_to_string_alloc(LOG_PRI(c->syslog_priority), &lvl_str);
-                if (r < 0)
-                        lvl_str = NULL;
+                log_facility_unshifted_to_string_alloc(c->syslog_priority >> 3, &fac_str);
+                log_level_to_string_alloc(LOG_PRI(c->syslog_priority), &lvl_str);
 
                 fprintf(f,
                         "%sSyslogFacility: %s\n"
                         "%sSyslogLevel: %s\n",
                         prefix, strna(fac_str),
                         prefix, strna(lvl_str));
-                free(lvl_str);
-                free(fac_str);
         }
 
         if (c->capabilities) {
-                char *t;
-                if ((t = cap_to_text(c->capabilities, NULL))) {
-                        fprintf(f, "%sCapabilities: %s\n",
-                                prefix, t);
-                        cap_free(t);
-                }
+                _cleanup_cap_free_charp_ char *t;
+
+                t = cap_to_text(c->capabilities, NULL);
+                if (t)
+                        fprintf(f, "%sCapabilities: %s\n", prefix, t);
         }
 
         if (c->secure_bits)
@@ -2049,12 +2041,11 @@ void exec_context_dump(ExecContext *c, FILE* f, const char *prefix) {
 
                 for (l = 0; l <= cap_last_cap(); l++)
                         if (!(c->capability_bounding_set_drop & ((uint64_t) 1ULL << (uint64_t) l))) {
-                                char *t;
+                                _cleanup_cap_free_charp_ char *t;
 
-                                if ((t = cap_to_name(l))) {
+                                t = cap_to_name(l);
+                                if (t)
                                         fprintf(f, " %s", t);
-                                        cap_free(t);
-                                }
                         }
 
                 fputs("\n", f);
diff --git a/src/libsystemd-bus/bus-dump.c b/src/libsystemd-bus/bus-dump.c
index df7cf6893a..78e7597ed5 100644
--- a/src/libsystemd-bus/bus-dump.c
+++ b/src/libsystemd-bus/bus-dump.c
@@ -19,8 +19,6 @@
   along with systemd; If not, see <http://www.gnu.org/licenses/>.
 ***/
 
-#include <sys/capability.h>
-
 #include "util.h"
 #include "capability.h"
 #include "strv.h"
@@ -281,12 +279,15 @@ static void dump_capabilities(
 
         for (;;) {
                 if (r > 0) {
+                        _cleanup_cap_free_charp_ char *t;
+
                         if (n > 0)
                                 fputc(' ', f);
                         if (n % 4 == 3)
                                 fputs("\n          ", f);
 
-                        fputs(cap_to_name(i), f);
+                        t = cap_to_name(i);
+                        fprintf(f, "%s", t);
                         n++;
                 }
 
diff --git a/src/shared/capability.c b/src/shared/capability.c
index 72c671cf84..f8ee1c6838 100644
--- a/src/shared/capability.c
+++ b/src/shared/capability.c
@@ -37,21 +37,17 @@
 #include "fileio.h"
 
 int have_effective_cap(int value) {
-        cap_t cap;
+        _cleanup_cap_free_ cap_t cap;
         cap_flag_value_t fv;
-        int r;
 
         cap = cap_get_proc();
         if (!cap)
                 return -errno;
 
         if (cap_get_flag(cap, value, CAP_EFFECTIVE, &fv) < 0)
-                r = -errno;
+                return -errno;
         else
-                r = fv == CAP_SET;
-
-        cap_free(cap);
-        return r;
+                return fv == CAP_SET;
 }
 
 unsigned long cap_last_cap(void) {
@@ -89,7 +85,7 @@ unsigned long cap_last_cap(void) {
 
 int capability_bounding_set_drop(uint64_t drop, bool right_now) {
         unsigned long i;
-        cap_t after_cap = NULL, temp_cap = NULL;
+        _cleanup_cap_free_ cap_t after_cap = NULL, temp_cap = NULL;
         cap_flag_value_t fv;
         int r;
 
@@ -102,10 +98,8 @@ int capability_bounding_set_drop(uint64_t drop, bool right_now) {
         if (!after_cap)
                 return -errno;
 
-        if (cap_get_flag(after_cap, CAP_SETPCAP, CAP_EFFECTIVE, &fv) < 0) {
-                cap_free(after_cap);
+        if (cap_get_flag(after_cap, CAP_SETPCAP, CAP_EFFECTIVE, &fv) < 0)
                 return -errno;
-        }
 
         if (fv != CAP_SET) {
                 static const cap_value_t v = CAP_SETPCAP;
@@ -162,13 +156,7 @@ int capability_bounding_set_drop(uint64_t drop, bool right_now) {
         r = 0;
 
 finish:
-        if (temp_cap)
-                cap_free(temp_cap);
-
-        if (after_cap) {
-                cap_set_proc(after_cap);
-                cap_free(after_cap);
-        }
+        cap_set_proc(after_cap);
 
         return r;
 }
diff --git a/src/shared/capability.h b/src/shared/capability.h
index 59469e56cb..64f86410ab 100644
--- a/src/shared/capability.h
+++ b/src/shared/capability.h
@@ -23,8 +23,20 @@
 
 #include <inttypes.h>
 #include <stdbool.h>
+#include <sys/capability.h>
+
+#include "util.h"
 
 unsigned long cap_last_cap(void);
 int have_effective_cap(int value);
 int capability_bounding_set_drop(uint64_t drop, bool right_now);
 int capability_bounding_set_drop_usermode(uint64_t drop);
+
+DEFINE_TRIVIAL_CLEANUP_FUNC(cap_t, cap_free);
+#define _cleanup_cap_free_ _cleanup_(cap_freep)
+
+static inline void cap_free_charpp(char **p) {
+        if (*p)
+                cap_free(*p);
+}
+#define _cleanup_cap_free_charp_ _cleanup_(cap_free_charpp)